^^^^ The problem related to vmlinux handling, it shouldn’t be trying this
^^^^ rather alien /proc/kallsyms at all…

/lib64/libpthread-2.10.2.so with build id 5c68f7afeb33309c78037e374b0deee84dd441f6 not found, continuing without symbols
/lib64/libc-2.10.2.so with build id eb4ec8fa8b2a5eb18cad173c92f27ed8887ed1c1 not found, continuing without symbols
/home/acme/bin/perf with build id a83ecfb519a788774a84d5ddde633c9ba56c03ab not found, continuing without symbols
/usr/sbin/openvpn with build id f2037a091ef36b591187a858d75e203690ea9409 not found, continuing without symbols
Failed to open /lib/modules/2.6.33-rc4-tip+/kernel/drivers/net/e1000e/e1000e.ko, continuing without symbols
Failed to open /lib/modules/2.6.33-rc4-tip+/kernel/drivers/net/wireless/iwlwifi/iwlcore.ko, continuing without symbols
<SNIP more complaints about not finding the right build-ids,
those will have to wait for ‘perf archive’ or plain
copying what was collected by ‘perf record’ on the x86_64,
source machine, see further below for an example of this>

While trying to fix the build-id generation so as not to produce duplicates, I noticed another problem that needs to be solved before we can introduce perf archive and be able to analyse a perf.data file recorded in one machine on another, possibly with a different architecture and OS.

The problem is similar to the relocatable kernel problem solved today: we need to have perf events that state where kernel modules were loaded, right now we are using the current /proc/modules to get that information, but it can no longer have some modules, unloaded after perf record and before perf report.

To properly fix that we need the kernel infrastructure to emit PERF_MODULE_LOAD/PERF_MODULE_UNLOAD events just like it does when DSOs get loaded by means of executable mmap, when it emits PERF_MMAP/PERF_MUNMAP events, so that there are no races and we can support long running perf record sessions where modules get loaded/unloaded.

Tomorrow I’ll work on synthesizing such events in perf record and then when all works we can do the kernel bits and stop synthesizing then in user space.